Lamp socket



July 30, 1940- En. BRYANT E1- AL 2,209,808

` LAMP SOCKET Filed-Oct'. 13, 1938 Inventors: Frank D Bryant., William RYoUn'g,

bg Wwf/f Their` Attonnes.

Patented July 30, 1940 PATENT OFFICE LAMP SOCKET .'Frank D. Bryant, Stratford, andv William R. Young, Fairiield, Conn., assignors to General Electric Company, a

corporation of New York Application October 13, 1938, Serial No. 234,798

2 Claims.

'Ihis invention relates to lamp sockets, and more particularly to a socket for incandescent lamps.

' It is an object of the invention to provide an improved switch mechanism for lamp sockets of the type indicated which provides relatively few parts and which may be easily assembled and manufactured at low cost.

In the accompanying drawing Fig. 1 is a view in elevation of a lamp socketincorporating the improved switch mechanism; Fig. 2 is a crosssectional view through the socket along the lines 2--2 of Fig. 1; Fig. 3 is a sectional view on the line 3 3 of Fig. 2, and Fig. 4 is an exploded view of a portion of the lamp socket and switch mechanism. l

Referring to Figs. 1 and 2 the lamp socket It is provided with a cylindrical casing ll of metal such as brass, or the like, which is tapered inwardly at I2 to provide an extension I3. The extension is provided with screw threads for mounting a lamp shade or reflector. The upper portion of the 'casing is provided with a cap l5 formed with a screw threaded nipple I6 for connection to a rigid conduit (not shown). A screw Il is mounted in the nipple and is adapted to engage the rigid conduit and lock it securely to the nipple. The cap I5 is provided with a iiangc I8 formed-with inwardly extending bosses I9 which frictionally engage the cylindrical casing and secure4 it to the' cap in a manner known in the art. The interior of the cap I5 is provided with a liner 20 of insulating material such as fiber, or the like, which serves to insulate the metallic cap from the conductors which extend through the nipple into engagement with the switch mechanism of the socket. In order to support the liner the cap is provided with inturned projections 2l. In a similar way the body 40 of the cylindrical casing is provided with an insulating lining 22 formed of ber, or the like, Y

and this lining snugly fits the contour of the casing and serves to insulate the switch mechanism and the lamp receptacle from the outer casing Il. i

Referring more particularly to Figs. 2 and 3, a base member 23 of insulating material is mounted within the cylindrical casing and is provided on its upper portion with a. switch mechanism and on its lower portion with a receptacle for an incandescent lamp or screw connector. The base 23 is supported within the casing by engagement with the tapered portion l2. The receptacle comprises a threaded shell 24 provided with inturned ears 25 at its upper end for connection to the base 23. In mounted position the shell fits snugly within the casing and is insulated therefrom by the lining 22. The ears 25 are secured to the base by screws 26 and 21. As shown more particularly by Fig. 2 the screw 21 extends into the base 23 a short distance only,

whereas the screw 26 passes through opening 26 to the upper side of the base and is fastened thereto by a nut 28. In order to provide means for securing one of the connecting wires to the screw shell a terminal member 29 is mounted on the base 23, and isl secured to the screw 26 by means of the nut 2B, the member is provided with a terminal screw 30 extending into an opening 3l formed in the base. Cooperating with the screw shell 24 is a centrally disposed contact 32 mounted in the base and secured thereto by means of a bolt 34 and a nut 35. The bolt 34 extends through the base, as shown more particularly in Fig. 2, and engages one contact of a switch mechanism now to 'be described.

The upper portion of the base is shaped to receive a switch mechanism for controlling the electric current which energizes the receptacle contacts. To this end the base is provided with a transverse groove 3B which is formed with a centrally disposed recess 31. In the form of the invention illustrated, the groove is semi-circular in shape, while the recess is made of rectangular configuration; however, it will be' apparent that the groove and recess may be given other forms. The recess is provided with spaced grooves 38 which lie on opposite sides thereof and form an "ofP position for the switch mechanism to be described later. Laterally adjacent the grooves 38 the recess is provided with a second pair oi' grooves 39 formed on each s ide thereof, and which are adapted to receive contact members 40 and 4|. 'I'he grooves 38 and 39 are separated by projections or hills 42. The contact 40 is of substantially L-shape, with the arm of the L resting in the bottom of the recess and being provided with an opening for receiving the bolt 34. In this manner the contact 40 is electrically connected to the center contact 32 forming part of' the lamp receptacle. 'Ihe end 'of the L-shaped contact is oi' V- shape and rests within the groove 39. The other stationary contact 4I is bent in the form of an angle and has one arm located in the groove 39 and is shaped in the form of a V similar to the end of the contact 40. The other arm of the angle rests in a groove 43 formed in the base 23 and is provided with a terminal screw 43' for receiving the bared end of an electric conductor. 'I'he end of the screw 43 is received within a recess 44 formed in the base member. In order to hold contact il in position upon-the base a cover plate 45 of insulating material such as ber, or the like, overlies the'contact and is secured to the base by means of the screw 26 and nut 28. The cover plate 45 is provided with a cutout recess 46 for receiving the head of *the screw 43. By reference to Fig. 2

it will be seen that the cover plate 45 is placed` beneath the terminal member 29, so that this Aas member is insulated adequately from the arm of the contact 40. From the construction just described it will be seen that the contact 4| is secured to the base by means of the insulating cover plate 45, whereas the contact 40 is held in position within the recess by means of the contact screw 34. This structure provides a simple and effective means of positioning the con-'- tacts within the base.

A movable switch-operating mechanism co operates withthe fixed contacts 40 and 4| and comprises a slider 41 of insulating material which is positioned within the groove 36 and is adapted to be reciprocated within the groove for operation of the switch. The slider element is cylindrical conforming to thel configuration of the groove 36 and is provided with a centrally disposed substantially rectangular enlarged portion 48 whichl rests within the recess 31. The enlarged portion of the slider element is provided with a transverseopening 49 which receives the roller contacts 50 at each side thereof. In the form of the invention shown the roller contacts comprise ball bearings which may be made of brass, or like material, and which cooperate with the fixed contacts 40 and 4I. In order to provide' an electrically conductive path between the roller contacts 50 and in order to press them tightly against the iixed contacts, a spring 5| is positioned within the opening 49 and presses the roller contacts outwardly against the iixed contacts in the manner indicated. The ends of the slider member project beyond the confines of the base 23 and pass through slots 52 formed in the insulating liner and the outer casing where they may be gripped by the hand and pushed back and forth to operate the switch mechanism.

It will be apparent that as the ends ci the slider element are pushed to and fro the ball bearing contacts will be positioned, .either in engagement with the contacts 40 and 4|, or in engagement with the grooves 38. While in engagement with the grooves 38 the switch is in cti position. To close the switch, the slider element is pushed to the right as shown in Figs. 1 and 3 to place the roller contacts in engagement with the fixed contacts so that the current ilows from one fixed contact to the other through the medium of the ball bearing contacts and the compression spring 5I. As the roller contacts move from on to on position they pass over the hill portions 42 and move laterally within the opening 49 in the slider member against the action of the spring 5 I. This construction makes it impossible to leave the switch in a partially open position because the projections or hills42 will force the roller bearings, either into engagement with the contact members, in on" position, or into engagement with the recesses 38 in oil position. When in on position the current from one of the conductors flows through the terminal member 29, the screw 26, the outer screw shell 24, through the incandescent lamp or other attached appliance, then through the Vcontact 32, to the screw 34, contact 40, movable contacts 50 and the spring 5l to the other fixed contact 4l and thence to the other conductor.

The construction described provides a simpliiied form of switch mechanism which is easily assembled and which may be manufactured at low cost. Due to the fact that the roller bearings are easily slidable laterally within the opening in the slider element, it is possible to` secure a switch which has a quick make" or break action between the fixed contacts and the movable contacts. The slider element 41 is retained within the groove 36 by the cover plate 45 and is limited in its lateral movement by engagement of the enlarged portion 48 with the end walls ot the recess 31. The ball bearings make two points ,of contact with the sides of the V-shaped iixed contacts thereby securing an adequate electrical connection between the switch contacts. The mechanism is rugged in construction and is one which will not easily get out of order because of the relatively few parts employed in the construction.

In assembling the lamp socket the receptacle and switch mechanism are first secured in operative position upon the hasel and the base is then slipped within the casing Il where it rests upon the tapered portion with the ends of the slider element positioned within the grooves 52 and the shell 24 positioned within the extension I3. Thereafter, the cap I5 is applied to the casing.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In a device of the class described, a casing having opposite grooves formed therein, a base member mounted in said casing having a recess therein, fixed contacts mounted on opposite sides of said recess, one of said contacts being L-shaped with an arm of the L resting on the top oi said base member, a slider element movably mounted insaid recess and having opposite ends extending through said grooves beyond the confines of said casing, roller bearings carried by said slide and engaging said iixed contacts, an insulating cover plate overlying said, recess and arm for maintaining said slider and L-shaped contact in position on said base, and receptacle means having a screw shell and a central contact mounted on said base and disposed within said casing, the other of said xed contacts being electrically connected to said central contact.

2. In a device of the class described, a base having a groove therein provided with a centrally disposed recess, iixed grooved contacts mounted on opposite sides of said recess, a slider element having a centrally enlarged portion located in said recess and conforming to the contour thereof and having arms mounted insaid groove. a plate of insulating material maintaining said contacts and slider in said recess, the enlarged portion of said slider element having a transverse opening therethrough, roller ball contact elements mounted for longitudinal movement in said opening, spring means electrically interconnecting said roller contacts and maintaining them within the grooves of said iixed contacts, a receptacle means having a screw shell and a central contact mounted on the bottom of' said FRANK D. BRYANT. WILLIAM R. YOUNG. 

